1. Field of the Invention
The invention in general relates to sonar systems, and more particularly, to a multibeam sonar system for imaging a target area.
2. Description of the Prior Art
Various sonar systems have been developed for obtaining an acoustic representation of a target area. For example, in a side looking sonar system, transducer equipment on board a carrier vehicle is operable to project acoustic energy toward the target area so as to impinge upon an extremely narrow region in the form of an elongated strip generally perpendicular to the direction of travel of the carrier vehicle and commonly referred to as an insonified region or strip. The reflected energy is received from the strip and with multiple transmissions and receptions, an acoustic representation of the target area may be displayed.
Since the strip is relatively narrow in the direction of travel, many systems employ multiple beam formation so that a plurality of adjacent strips may be imaged with a single acoustic transmission, thereby allowing for a greater carrier speed and an increase in the mapping rate.
Multibeam side look sonars, however, sometimes provide poorer images than a single beam system having the same frequency, range and resolution. It is believed that the degradation is due to acoustic energy from one strip scattering into the next adjacent strips of the multibeam system.